MORE than 70 Welsh patients have caught a new superbug which is resistant to virtually all antibiotics, Wales on Sunday can reveal.

There is growing concern across the UK that antibiotic-resistant infections caused by the bug Stenotrophomonas maltophilia – known as Steno – are on the increase.

But Welsh health experts have been quick to stress that such cases are rare compared to those caused by the superbug MRSA and E.coli.

Doctors studying the genetic code of Steno are worried about its ability to shrug off all but a couple of antibiotics.

But Dr Robin Howe, a consultant microbiologist, said Steno – which is found naturally in the environment – is not “another killer superbug”.

Dr Howe, head of the Welsh antimicrobial resistance programme for the National Public Health Service, said: “Stenotrophomonas is an environmental bacteria that is found everywhere – it has even been found in Antarctic ice cores. Interestingly, it is actually used on golf putting greens to get rid of brown-patch fungus.

“It is not very virulent and any infections in humans are in those who are very immuno-compromised, for example in people who have had a bone marrow transplant, but even in those patients it does not cause a particularly virulent infection.

“However, it is true that it is resistant to a lot of antibiotics – there are only one or two which are reliably effective against this bug.

“But I would be surprised if people infected with this bug did not respond to antibiotics.”

Steno thrives in moist environments such as around taps and shower heads and has a distinct method of infecting patients, getting into their systems through devices such as catheters or ventilation tubes that have been left in place for a long time.

Steno can stick to a catheter or ventilator tube and grow into a coating which is difficult to remove by normal cleaning. From here it can enter a patient’s bloodstream or lungs. In weakened patients, this can cause blood poisoning or pneumonia.

Dr Howe said: “The bug is not very good at causing infections, therefore the antibiotics we do have can work with the patient’s natural defences to fight off the infection.

“People who are very immuno-compromised will occasionally get infections, but this is just something that we have to deal with in medicine.

“It would be wrong to say that this is a new killer superbug – we had 73 cases last year in comparison to E.coli, which caused more than 1,000 bloodstream infections in patients.”

Researchers have now uncovered a complete blueprint of the genetic code (or genome) of Steno, which was published earlier this week in the journal Genome Biology.

It is hoped that this breakthrough will help scientists understand how Steno causes infections and it could lead to the development of new treatments.

Dr Matthew Avison, from the University of Bristol, who co-led the research team, said: “This is the latest in an ever-increasing list of antibiotic-resistant hospital superbugs. The degree of resistance it shows is very worrying. Strains are now emerging that are resistant to all available antibiotics, and so new drugs capable of combating these pan-resistant strains are currently in development.”

And Dr Lisa Crossman, from the Wellcome Trust Sanger Institute in Hinxton, Cambridgeshire, who also took part in the research, said: “The genome sequence should help us to combat these properties. For example, if we know which proteins cause it to stick to surfaces, we could try to develop biochemical compounds that interfere with this interaction.

“If we understand its antibiotic resistance mechanisms, we might be able to design inhibitors that block them.”